1 Introduction
2 Experiment Program
2.1 Material Properties
2.1.1 Cement and Aggregates
Compound | FA cement (%) |
---|---|
Silicon-di-oxide (SiO2) | 32.0 |
Aluminium oxide (Al2O3) | 10.0 |
Ferric oxide (Fe2O3) | 6.0 |
Calcium oxide (CaO) | 44 |
Magnesium oxide (MgO) | 2.0 |
Sulphur tri oxide (SO3) | 2.5 |
Loss on ignition | 3.5 |
Physical properties | |
Pozzolonic material used (fly ash %) | 20 |
28 days compressive strength | 48 |
Fineness (m2/Kg) | 363 |
Specific gravity | 2.936 |
Specific surface area (Blaine) (cm2/g) | 4928 |
Relative absorption (%) | 13.25 |
Materials/m3 of concrete | Water | Cement | Fine aggregate | Coarse aggregate |
---|---|---|---|---|
kg/m3 | 191.6 | 399 | 540 | 1175 |
Mix ratio | 0.48 | 1 | 1.353 | 2.944 |
2.1.2 Rice Husk Ash
Ratio | SiO2 (91.79%) | Al2O3 | Fe2O3 | CaO | MgO | Na2O | K2O | Others | LOI | Total | |
---|---|---|---|---|---|---|---|---|---|---|---|
R* | NR* | ||||||||||
% | 90.21 | 1.58 | 2.12 | 0.80 | 1.27 | 0.67 | 0.14 | 0.76 | 0.89 | 1.56 | 100 |
2.1.3 Lime Powder (LP)
2.2 Mixing Systems
Mix designations | Systems |
---|---|
FAC | Fly ash cement |
FRL5 | Replacement of + 5% RHA + 5% LP |
FRL10 | Replacement of + 10% RHA + 10% LP |
FRL15 | Replacement of + 15% RHA + 15% LP |
FRL20 | Replacement of + 20% RHA + 20% LP |
FRL5–20 | Replacement of + 5% RHA + 20% LP |
FRL10–20 | Replacement of + 10% RHA + 20% LP |
FRL15–20 | Replacement of + 15% RHA + 20% LP |
2.3 Property Evaluation Tests
2.3.1 Compression Test
2.3.2 Tests for Density and Permeable Voids
2.4 Characterization Techniques
2.4.1 XRD and SEM/EDS
2.4.2 Thermogravimetry and Differential Thermal Analysis
3 Results and Discussion
3.1 Compression Test
3.1.1 Tests for Density, Permeable Voids and Water Absorption
Mix systems | Absorption after immersion (B−A)/A × 100 (%) | Absorption after immersion and boiling (C−A)/A × 100 (%) | Bulk density, dry A/(C−D) × ρ [g1] (mg/m3) | Bulk density after immersion B/(C−D) × ρ | Bulk density after immersion and boiling C/(C−D) × ρ | Apparent density A/(A−D) × ρ [g2] (mg/m3) | Volume of permeable voids (%) [(g2−g1)/g2] × 100 |
---|---|---|---|---|---|---|---|
FAC | 8.914 | 8.706 | 1.986 | 2.163 | 2.159 | 2.402 | 17.294 |
FRL5 | 8.109 | 8.271 | 1.965 | 2.125 | 2.128 | 2.347 | 16.256 |
FRL10 | 8.585 | 8.647 | 1.988 | 2.159 | 2.160 | 2.401 | 17.192 |
FRL15 | 10.431 | 11.531 | 1.968 | 2.174 | 2.195 | 2.546 | 22.697 |
FRL20 | 9.188 | 10.398 | 1.938 | 2.116 | 2.139 | 2.427 | 20.149 |
3.2 Characterization Techniques
3.2.1 X-ray Diffraction
3.2.2 SEM and EDS
3.2.3 Tg/dta
Results | Wt. of Ca(OH)2 (%) | Wt. of C–S–H (%) | Wt. of CaCO3 (%) |
---|---|---|---|
FAC | 3.03 | 9.5 | 0.97 |
FRL5 | 1.55 | 9.48 | 0.83 |
FRL10 | 1.50 | 10.48 | 0.97 |
FRL15 | 1.36 | 9.75 | 1.39 |
FRL20 | 1.48 | 7.9 | 1.42 |